asyncua.server.history_sql

Complexity

Total Complexity

51

Size/Duplication

Total Lines	281
Duplicated Lines	0 %

Importance

Changes

0

18 Methods

Rating	Name	Duplication	Size	Complexity
A	HistorySQLite._list_to_sql_str()	0	4	2
B	HistorySQLite.read_event_history()	0	28	7
A	HistorySQLite.init()	0	2	1
A	HistorySQLite._get_select_clauses()	0	15	4
B	HistorySQLite._get_bounds()	0	20	7
A	HistorySQLite._get_event_fields()	0	16	3
B	HistorySQLite.read_node_history()	0	28	5
A	HistorySQLite.save_event()	0	22	4
A	HistorySQLite.execute_sql_delete()	0	5	2
A	HistorySQLite.new_historized_node()	0	16	2
A	HistorySQLite.stop()	0	4	1
A	HistorySQLite._format_event()	0	21	2
A	HistorySQLite.__init__()	0	7	1
A	HistorySQLite._get_event_columns()	0	5	2
A	HistorySQLite._get_table_name()	0	2	1
A	HistorySQLite._execute_sql()	0	2	1
A	HistorySQLite.new_historized_event()	0	18	2
A	HistorySQLite.save_node_value()	0	25	4

import logging
from typing import Iterable, Coroutine, Optional
from datetime import timedelta
from datetime import datetime
from asyncio import get_event_loop
import sqlite3

from asyncua import ua
from ..ua.ua_binary import variant_from_binary, variant_to_binary
from ..common import Buffer, Event, get_event_properties_from_type_node
from .history import HistoryStorageInterface

__all__ = ["HistorySQLite"]


class HistorySQLite(HistoryStorageInterface):
    """
    history backend which stores data values and object events in a SQLite database
    this backend is intended to only be accessed via OPC UA, therefore all UA Variants saved in
    the history database are in binary format (SQLite BLOBs)
    note that PARSE_DECLTYPES is active so certain data types (such as datetime) will not be BLOBs
    """

    def __init__(self, path="history.db", loop=None):
        self.logger = logging.getLogger(__name__)
        self._datachanges_period = {}
        self._db_file = path
        self._event_fields = {}
        self._conn: Optional[sqlite3.Connection] = None
        self._loop = loop or get_event_loop()

    async def init(self):
        self._conn = sqlite3.connect(self._db_file, detect_types=sqlite3.PARSE_DECLTYPES, check_same_thread=False)

    async def stop(self):
        await self._loop.run_in_executor(None, self._conn.close)
        self._conn = None
        self.logger.info('Historizing SQL connection closed')

    async def _execute_sql(self, sql: str, params: Iterable = None):
        return await self._loop.run_in_executor(None, self._conn.execute, sql, params or ())

    async def new_historized_node(self, node_id, period, count=0):
        table = self._get_table_name(node_id)
        self._datachanges_period[node_id] = period, count
        # create a table for the node which will store attributes of the DataValue object
        # note: Value/VariantType TEXT is only for human reading, the actual data is stored in VariantBinary column
        try:
            await self._execute_sql(f'CREATE TABLE "{table}" (_Id INTEGER PRIMARY KEY NOT NULL,'
                                    ' ServerTimestamp TIMESTAMP,'
                                    ' SourceTimestamp TIMESTAMP,'
                                    ' StatusCode INTEGER,'
                                    ' Value TEXT,'
                                    ' VariantType TEXT,'
                                    ' VariantBinary BLOB)', None)

        except sqlite3.Error as e:
            self.logger.info("Historizing SQL Table Creation Error for %s: %s", node_id, e)

    async def execute_sql_delete(self, condition: str, args: Iterable, table: str, node_id):
        try:
            await self._execute_sql(f'DELETE FROM "{table}" WHERE {condition}', args)
        except sqlite3.Error as e:
            self.logger.error("Historizing SQL Delete Old Data Error for %s: %s", node_id, e)

    async def save_node_value(self, node_id, datavalue):
        table = self._get_table_name(node_id)
        # insert the data change into the database
        try:
            await self._execute_sql(f'INSERT INTO "{table}" VALUES (NULL, ?, ?, ?, ?, ?, ?)', (
                datavalue.ServerTimestamp,
                datavalue.SourceTimestamp,
                datavalue.StatusCode.value,
                str(datavalue.Value.Value),
                datavalue.Value.VariantType.name,
                sqlite3.Binary(variant_to_binary(datavalue.Value))
            ))
        except sqlite3.Error as e:
            self.logger.error("Historizing SQL Insert Error for %s: %s", node_id, e)
        # get this node's period from the period dict and calculate the limit
        period, count = self._datachanges_period[node_id]
        if period:
            # after the insert, if a period was specified delete all records older than period
            date_limit = datetime.utcnow() - period
            await self.execute_sql_delete("SourceTimestamp < ?", (date_limit,), table, node_id)
        if count:
            # ensure that no more than count records are stored for the specified node
            await self.execute_sql_delete(
                'SourceTimestamp = (SELECT CASE WHEN COUNT(*) > ? '
                f'THEN MIN(SourceTimestamp) ELSE NULL END FROM "{table}")', (count,), table, node_id)

    async def read_node_history(self, node_id, start, end, nb_values):
        
        table = self._get_table_name(node_id)
        start_time, end_time, order, limit = self._get_bounds(start, end, nb_values)
        cont = None
        results = []
        # select values from the database; recreate UA Variant from binary
        try:
            rows = await self._execute_sql(
                    f'SELECT * FROM "{table}" WHERE "SourceTimestamp" BETWEEN ? AND ? '
                    f'ORDER BY "_Id" {order} LIMIT ?', (start_time, end_time, limit,)
            )
            for row in rows:
                # rebuild the data value object
                dv = ua.DataValue(variant_from_binary(Buffer(row[6])))
                dv.ServerTimestamp = row[1]
                dv.SourceTimestamp = row[2]
                dv.StatusCode = ua.StatusCode(row[3])
                results.append(dv)

        except sqlite3.Error as e:
            self.logger.error("Historizing SQL Read Error for %s: %s", node_id, e)

        if nb_values:
            if len(results) > nb_values:
                cont = results[nb_values].SourceTimestamp
            results = results[:nb_values]
        return results, cont

    async def new_historized_event(self, source_id, evtypes, period, count=0):
        # get all fields for the event type nodes
        ev_fields = await self._get_event_fields(evtypes)
        self._datachanges_period[source_id] = period
        self._event_fields[source_id] = ev_fields
        table = self._get_table_name(source_id)
        columns = self._get_event_columns(ev_fields)
        # create a table for the event which will store fields generated by the source object's events
        # note that _Timestamp is for SQL query, _EventTypeName is for debugging, be careful not to create event
        # properties with these names
        try:
            self._execute_sql(
                f'CREATE TABLE "{table}" '
                f'(_Id INTEGER PRIMARY KEY NOT NULL, _Timestamp TIMESTAMP, _EventTypeName TEXT, {columns})',
                None
            )
        except sqlite3.Error as e:
            self.logger.info("Historizing SQL Table Creation Error for events from %s: %s", source_id, e)

    async def save_event(self, event):
        table = self._get_table_name(event.SourceNode)
        columns, placeholders, evtup = self._format_event(event)
        event_type = event.EventType  # useful for troubleshooting database
        # insert the event into the database
        try:
            await self._execute_sql(
                f'INSERT INTO "{table}" ("_Id", "_Timestamp", "_EventTypeName", {columns}) '
                f'VALUES (NULL, "{event.Time}", "{event_type}", {placeholders})',
                evtup
            )
        except sqlite3.Error as e:
            self.logger.error("Historizing SQL Insert Error for events from %s: %s", event.SourceNode, e)
        # get this node's period from the period dict and calculate the limit
        period = self._datachanges_period[event.SourceNode]
        if period:
            # after the insert, if a period was specified delete all records older than period
            date_limit = datetime.utcnow() - period
            try:
                await self._execute_sql(f'DELETE FROM "{table}" WHERE Time < ?', (date_limit.isoformat(' '),))
            except sqlite3.Error as e:
                self.logger.error("Historizing SQL Delete Old Data Error for events from %s: %s", event.SourceNode, e)

    async def read_event_history(self, source_id, start, end, nb_values, evfilter):
        table = self._get_table_name(source_id)
        start_time, end_time, order, limit = self._get_bounds(start, end, nb_values)
        clauses, clauses_str = self._get_select_clauses(source_id, evfilter)
        cont = None
        cont_timestamps = []
        results = []
        # select events from the database; SQL select clause is built from EventFilter and available fields
        try:
            for row in await self._execute_sql(
                    f'SELECT "_Timestamp", {clauses_str} FROM "{table}" '
                    f'WHERE "_Timestamp" BETWEEN ? AND ? ORDER BY "_Id" {order} LIMIT ?',
                    (start_time, end_time, limit)):
                fdict = {}
                cont_timestamps.append(row[0])
                for i, field in enumerate(row[1:]):
                    if field is not None:
                        fdict[clauses[i]] = variant_from_binary(Buffer(field))
                    else:
                        fdict[clauses[i]] = ua.Variant(None)
                results.append(Event.from_field_dict(fdict))
        except sqlite3.Error as e:
            self.logger.error("Historizing SQL Read Error events for node %s: %s", source_id, e)
        if nb_values:
            if len(results) > nb_values:  # start > ua.get_win_epoch() and
                cont = cont_timestamps[nb_values]
            results = results[:nb_values]
        return results, cont

    def _get_table_name(self, node_id):
        return f"{node_id.NamespaceIndex}_{node_id.Identifier}"

    async def _get_event_fields(self, evtypes):
        """
        Get all fields from the event types that are to be historized
        Args:
            evtypes: List of event type nodes

        Returns: List of fields for all event types
        """
        # get all fields from the event types that are to be historized
        ev_aggregate_fields = []
        for event_type in evtypes:
            ev_aggregate_fields.extend((await get_event_properties_from_type_node(event_type)))
        ev_fields = []
        for field in set(ev_aggregate_fields):
            ev_fields.append((await field.get_display_name()).Text)
        return ev_fields

    @staticmethod
    def _get_bounds(start, end, nb_values):
        order = "ASC"
        if start is None or start == ua.get_win_epoch():
            order = "DESC"
            start = ua.get_win_epoch()
        if end is None or end == ua.get_win_epoch():
            end = datetime.utcnow() + timedelta(days=1)
        if start < end:
            start_time = start.isoformat(" ")
            end_time = end.isoformat(" ")
        else:
            order = "DESC"
            start_time = end.isoformat(" ")
            end_time = start.isoformat(" ")
        if nb_values:
            limit = nb_values + 1  # add 1 to the number of values for retrieving a continuation point
        else:
            limit = -1  # in SQLite a LIMIT of -1 returns all results
        return start_time, end_time, order, limit

    def _format_event(self, event):
        """
        Convert an event object triggered by the subscription into ordered lists for the SQL insert string

        Args:
            event: The event returned by the subscription

        Returns: List of event fields (SQL column names), List of '?' placeholders, Tuple of variant binaries
        """
        placeholders = []
        ev_variant_binaries = []
        ev_variant_dict = event.get_event_props_as_fields_dict()
        names = list(ev_variant_dict.keys())
        names.sort()  # sort alphabetically since dict is not sorted
        # split dict into two synchronized lists which will be converted to SQL strings
        # note that the variants are converted to binary objects for storing in SQL BLOB format
        for name in names:
            variant = ev_variant_dict[name]
            placeholders.append("?")
            ev_variant_binaries.append(sqlite3.Binary(variant_to_binary(variant)))
        return self._list_to_sql_str(names), self._list_to_sql_str(placeholders, False), tuple(ev_variant_binaries)

    def _get_event_columns(self, ev_fields):
        fields = []
        for field in ev_fields:
            fields.append(field + " BLOB")
        return self._list_to_sql_str(fields, False)

    def _get_select_clauses(self, source_id, evfilter):
        s_clauses = []
        for select_clause in evfilter.SelectClauses:
            try:
                if not select_clause.BrowsePath:
                    s_clauses.append(select_clause.Attribute.name)
                else:
                    name = select_clause.BrowsePath[0].Name
                    s_clauses.append(name)
            except AttributeError:
                self.logger.warning("Historizing SQL OPC UA Select Clause Warning for node %s,"
                                    " Clause: %s:", source_id, select_clause)
        # remove select clauses that the event type doesn't have; SQL will error because the column doesn't exist
        clauses = [x for x in s_clauses if x in self._event_fields[source_id]]
        return clauses, self._list_to_sql_str(clauses)

    @staticmethod
    def _list_to_sql_str(ls, quotes=True):
        items = [f'"{item}"' if quotes else str(item) for item in ls]
        return ", ".join(items)